Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {Initializable} from "openzeppelin-upgradeable/proxy/utils/Initializable.sol";
import {AccessControlEnumerableUpgradeable} from
    "openzeppelin-upgradeable/access/AccessControlEnumerableUpgradeable.sol";
import {Math} from "openzeppelin/utils/math/Math.sol";
import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
import {SafeERC20Upgradeable} from "openzeppelin-upgradeable/token/ERC20/utils/SafeERC20Upgradeable.sol";

import {ProtocolEvents} from "./interfaces/ProtocolEvents.sol";
import {IDepositContract} from "./interfaces/IDepositContract.sol";
import {IMETH} from "./interfaces/IMETH.sol";
import {IOracleReadRecord, OracleRecord} from "./interfaces/IOracle.sol";
import {IPauserRead} from "./interfaces/IPauser.sol";
import {IStaking, IStakingReturnsWrite, IStakingInitiationRead} from "./interfaces/IStaking.sol";
import {UnstakeRequest, IUnstakeRequestsManager} from "./interfaces/IUnstakeRequestsManager.sol";

import {ILiquidityBuffer} from "./liquidityBuffer/interfaces/ILiquidityBuffer.sol";

/// @notice Events emitted by the staking contract.
interface StakingEvents {
    /// @notice Emitted when a user stakes ETH and receives mETH.
    /// @param staker The address of the user staking ETH.
    /// @param ethAmount The amount of ETH staked.
    /// @param mETHAmount The amount of mETH received.
    event Staked(address indexed staker, uint256 ethAmount, uint256 mETHAmount);

    /// @notice Emitted when a user unstakes mETH in exchange for ETH.
    /// @param id The ID of the unstake request.
    /// @param staker The address of the user unstaking mETH.
    /// @param ethAmount The amount of ETH that the staker will receive.
    /// @param mETHLocked The amount of mETH that will be burned.
    event UnstakeRequested(uint256 indexed id, address indexed staker, uint256 ethAmount, uint256 mETHLocked);

    /// @notice Emitted when a user claims their unstake request.
    /// @param id The ID of the unstake request.
    /// @param staker The address of the user claiming their unstake request.
    event UnstakeRequestClaimed(uint256 indexed id, address indexed staker);

    /// @notice Emitted when a validator has been initiated (i.e. the protocol has deposited into the deposit contract).
    /// @param id The ID of the validator which is the hash of its pubkey.
    /// @param operatorID The ID of the node operator to which the validator belongs to.
    /// @param pubkey The pubkey of the validator.
    /// @param amountDeposited The amount of ETH deposited into the deposit contract for that validator.
    event ValidatorInitiated(bytes32 indexed id, uint256 indexed operatorID, bytes pubkey, uint256 amountDeposited);

    /// @notice Emitted when the protocol has allocated ETH to the UnstakeRequestsManager.
    /// @param amount The amount of ETH allocated to the UnstakeRequestsManager.
    event AllocatedETHToUnstakeRequestsManager(uint256 amount);

    /// @notice Emitted when the protocol has allocated ETH to use for deposits into the deposit contract.
    /// @param amount The amount of ETH allocated to deposits.
    event AllocatedETHToDeposits(uint256 amount);

    /// @notice Emitted when the protocol has received returns from the returns aggregator.
    /// @param amount The amount of ETH received.
    event ReturnsReceived(uint256 amount);

    /// @notice Emitted when the protocol has received returns from the returns aggregator.
    /// @param amount The amount of ETH received.
    event ReturnsReceivedFromLiquidityBuffer(uint256 amount);

    /// @notice Emitted when the protocol has allocated ETH to the liquidity buffer.
    /// @param amount The amount of ETH allocated to the liquidity buffer.
    event AllocatedETHToLiquidityBuffer(uint256 amount);
}

/// @title Staking
/// @notice Manages stake and unstake requests by users, keeps track of the total amount of ETH controlled by the
/// protocol, and initiates new validators.
contract Staking is Initializable, AccessControlEnumerableUpgradeable, IStaking, StakingEvents, ProtocolEvents {
    // Errors.
    error DoesNotReceiveETH();
    error InvalidConfiguration();
    error MaximumValidatorDepositExceeded();
    error MaximumMETHSupplyExceeded();
    error MinimumStakeBoundNotSatisfied();
    error MinimumUnstakeBoundNotSatisfied();
    error MinimumValidatorDepositNotSatisfied();
    error NotEnoughDepositETH();
    error NotEnoughUnallocatedETH();
    error NotReturnsAggregator();
    error NotLiquidityBuffer();
    error NotUnstakeRequestsManager();
    error Paused();
    error PreviouslyUsedValidator();
    error ZeroAddress();
    error InvalidDepositRoot(bytes32);
    error StakeBelowMinimumMETHAmount(uint256 methAmount, uint256 expectedMinimum);
    error UnstakeBelowMinimumETHAmount(uint256 ethAmount, uint256 expectedMinimum);

    error InvalidWithdrawalCredentialsWrongLength(uint256);
    error InvalidWithdrawalCredentialsNotETH1(bytes12);
    error InvalidWithdrawalCredentialsWrongAddress(address);

    /// @notice Role allowed trigger administrative tasks such as allocating funds to / withdrawing surplusses from the
    /// UnstakeRequestsManager and setting various parameters on the contract.
    bytes32 public constant STAKING_MANAGER_ROLE = keccak256("STAKING_MANAGER_ROLE");

    /// @notice Role allowed to allocate funds to unstake requests manager and reserve funds to deposit into the
    /// validators.
    bytes32 public constant ALLOCATOR_SERVICE_ROLE = keccak256("ALLOCATER_SERVICE_ROLE");

    /// @notice Role allowed to initiate new validators by sending funds from the allocatedETHForDeposits balance
    /// to the beacon chain deposit contract.
    bytes32 public constant INITIATOR_SERVICE_ROLE = keccak256("INITIATOR_SERVICE_ROLE");

    /// @notice Role to manage the staking allowlist.
    bytes32 public constant STAKING_ALLOWLIST_MANAGER_ROLE = keccak256("STAKING_ALLOWLIST_MANAGER_ROLE");

    /// @notice Role allowed to stake ETH when allowlist is enabled.
    bytes32 public constant STAKING_ALLOWLIST_ROLE = keccak256("STAKING_ALLOWLIST_ROLE");

    /// @notice Role allowed to top up the unallocated ETH in the protocol.
    bytes32 public constant TOP_UP_ROLE = keccak256("TOP_UP_ROLE");

    /// @notice Payload struct submitted for validator initiation.
    /// @dev See also {initiateValidatorsWithDeposits}.
    struct ValidatorParams {
        uint256 operatorID;
        uint256 depositAmount;
        bytes pubkey;
        bytes withdrawalCredentials;
        bytes signature;
        bytes32 depositDataRoot;
    }

    /// @notice Keeps track of already initiated validators.
    /// @dev This is tracked to ensure that we never deposit for the same validator public key twice, which is a base
    /// assumption of this contract and the related off-chain accounting.
    mapping(bytes pubkey => bool exists) public usedValidators;

    /// @inheritdoc IStakingInitiationRead
    /// @dev This is needed to account for ETH that is still in flight, i.e. that has been sent to the deposit contract
    /// but has not been processed by the beacon chain yet. Once the off-chain oracle detects those deposits, they are
    /// recorded as `totalDepositsProcessed` in the oracle contract to avoid double counting. See also
    /// {totalControlled}.
    uint256 public totalDepositedInValidators;

    /// @inheritdoc IStakingInitiationRead
    uint256 public numInitiatedValidators;

    /// @notice The amount of ETH that is used to allocate to deposits and fill the pending unstake requests.
    uint256 public unallocatedETH;

    /// @notice The amount of ETH that is used deposit into validators.
    uint256 public allocatedETHForDeposits;

    /// @notice The minimum amount of ETH users can stake.
    uint256 public minimumStakeBound;

    /// @notice The minimum amount of mETH users can unstake.
    uint256 public minimumUnstakeBound;

    /// @notice When staking on Ethereum, validators must go through an entry queue to bring money into the system, and
    /// an exit queue to bring it back out. The entry queue increases in size as more people want to stake. While the
    /// money is in the entry queue, it is not earning any rewards. When a validator is active, or in the exit queue, it
    /// is earning rewards. Once a validator enters the entry queue, the only way that the money can be retrieved is by
    /// waiting for it to become active and then to exit it again. As of July 2023, the entry queue is approximately 40
    /// days and the exit queue is 0 days (with ~6 days of processing time).
    ///
    /// In a non-optimal scenario for the protocol, a user could stake (for example) 32 ETH to receive mETH, wait
    /// until a validator enters the queue, and then request to unstake to recover their 32 ETH. Now we have 32 ETH in
    /// the system which affects the exchange rate, but is not earning rewards.
    ///
    /// In this case, the 'fair' thing to do would be to make the user wait for the queue processing to finish before
    /// returning their funds. Because the tokens are fungible however, we have no way of matching 'pending' stakes to a
    /// particular user. This means that in order to fulfill unstake requests quickly, we must exit a different
    /// validator to return the user's funds. If we exit a validator, we can return the funds after ~5 days, but the
    /// original 32 ETH will not be earning for another 35 days, leading to a small but repeatable socialised loss of
    /// efficiency for the protocol. As we can only exit validators in chunks of 32 ETH, this case is also exacerbated
    /// by a user unstaking smaller amounts of ETH.
    ///
    /// To compensate for the fact that these two queues differ in length, we apply an adjustment to the exchange rate
    /// to reflect the difference and mitigate its effect on the protocol. This protects the protocol from the case
    /// above, and also from griefing attacks following the same principle. Essentially, when you stake you are
    /// receiving a value of mETH that discounts ~35 days worth of rewards in return for being able to access your
    /// money without waiting the full 40 days when unstaking. As the adjustment is applied to the exchange rate, this
    /// results in a small 'improvement' to the rate for all existing stakers (i.e. it is not a fee levied by the
    /// protocol itself).
    ///
    /// As the adjustment is applied to the exchange rate, the result is reflected in any user interface which shows the
    /// amount of mETH received when staking, meaning there is no surprise for users when staking or unstaking.
    /// @dev The value is in basis points (1/10000).
    uint16 public exchangeAdjustmentRate;

    /// @dev A basis point (often denoted as bp, 1bp = 0.01%) is a unit of measure used in finance to describe
    /// the percentage change in a financial instrument. This is a constant value set as 10000 which represents
    /// 100% in basis point terms.
    uint16 internal constant _BASIS_POINTS_DENOMINATOR = 10_000;

    /// @notice The maximum amount the exchange adjustment rate (10%) that can be set by the admin.
    uint16 internal constant _MAX_EXCHANGE_ADJUSTMENT_RATE = _BASIS_POINTS_DENOMINATOR / 10; // 10%

    /// @notice The minimum amount of ETH that the staking contract can send to the deposit contract to initiate new
    /// validators.
    /// @dev This is used as an additional safeguard to prevent sending deposits that would result in non-activated
    /// validators (since we don't do top-ups), that would need to be exited again to get the ETH back.
    uint256 public minimumDepositAmount;

    /// @notice The maximum amount of ETH that the staking contract can send to the deposit contract to initiate new
    /// validators.
    /// @dev This is used as an additional safeguard to prevent sending too large deposits. While this is not a critical
    /// issue as any surplus >32 ETH (at the time of writing) will automatically be withdrawn again at some point, it is
    /// still undesireable as it locks up not-earning ETH for the duration of the round trip decreasing the efficiency
    /// of the protocol.
    uint256 public maximumDepositAmount;

    /// @notice The beacon chain deposit contract.
    /// @dev ETH will be sent there during validator initiation.
    IDepositContract public depositContract;

    /// @notice The mETH token contract.
    /// @dev Tokens will be minted / burned during staking / unstaking.
    IMETH public mETH;

    /// @notice The oracle contract.
    /// @dev Tracks ETH on the beacon chain and other accounting relevant quantities.
    IOracleReadRecord public oracle;

    /// @notice The pauser contract.
    /// @dev Keeps the pause state across the protocol.
    IPauserRead public pauser;

    /// @notice The contract tracking unstake requests and related allocation and claim operations.
    IUnstakeRequestsManager public unstakeRequestsManager;

    /// @notice The address to receive beacon chain withdrawals (i.e. validator rewards and exits).
    /// @dev Changing this variable will not have an immediate effect as all exisiting validators will still have the
    /// original value set.
    address public withdrawalWallet;

    /// @notice The address for the returns aggregator contract to push funds.
    /// @dev See also {receiveReturns}.
    address public returnsAggregator;

    /// @notice The staking allowlist flag which, when enabled, allows staking only for addresses in allowlist.
    bool public isStakingAllowlist;

    /// @inheritdoc IStakingInitiationRead
    /// @dev This will be used to give off-chain services a sensible point in time to start their analysis from.
    uint256 public initializationBlockNumber;

    /// @notice The maximum amount of mETH that can be minted during the staking process.
    /// @dev This is used as an additional safeguard to create a maximum stake amount in the protocol. As the protocol
    /// scales up this value will be increased to allow for more staking.
    uint256 public maximumMETHSupply;

    /// @notice The address for the liquidity buffer contract to push funds.
    /// @dev See also {receiveReturnsFromLiquidityBuffer}.
    ILiquidityBuffer public liquidityBuffer;

    /// @notice Configuration for contract initialization.
    struct Init {
        address admin;
        address manager;
        address allocatorService;
        address initiatorService;
        address returnsAggregator;
        address withdrawalWallet;
        IMETH mETH;
        IDepositContract depositContract;
        IOracleReadRecord oracle;
        IPauserRead pauser;
        IUnstakeRequestsManager unstakeRequestsManager;
    }

    constructor() {
        _disableInitializers();
    }

    /// @notice Inititalizes the contract.
    /// @dev MUST be called during the contract upgrade to set up the proxies state.
    function initialize(Init memory init) external initializer {
        __AccessControlEnumerable_init();

        _grantRole(DEFAULT_ADMIN_ROLE, init.admin);
        _grantRole(STAKING_MANAGER_ROLE, init.manager);
        _grantRole(ALLOCATOR_SERVICE_ROLE, init.allocatorService);
        _grantRole(INITIATOR_SERVICE_ROLE, init.initiatorService);
        // Intentionally does not set anyone as the TOP_UP_ROLE as it will only be granted
        // in the off-chance that the top up functionality is required.

        // Set up roles for the staking allowlist. Intentionally do not grant anyone the
        // STAKING_ALLOWLIST_MANAGER_ROLE as it will only be granted later.
        _setRoleAdmin(STAKING_ALLOWLIST_MANAGER_ROLE, STAKING_MANAGER_ROLE);
        _setRoleAdmin(STAKING_ALLOWLIST_ROLE, STAKING_ALLOWLIST_MANAGER_ROLE);

        mETH = init.mETH;
        depositContract = init.depositContract;
        oracle = init.oracle;
        pauser = init.pauser;
        returnsAggregator = init.returnsAggregator;
        unstakeRequestsManager = init.unstakeRequestsManager;
        withdrawalWallet = init.withdrawalWallet;

        minimumStakeBound = 0.1 ether;
        minimumUnstakeBound = 0.01 ether;
        minimumDepositAmount = 32 ether;
        maximumDepositAmount = 32 ether;
        isStakingAllowlist = true;
        initializationBlockNumber = block.number;

        // Set the maximum mETH supply to some sensible amount which is expected to be changed as the
        // protocol ramps up.
        maximumMETHSupply = 1024 ether;
    }
        
    function initializeV2(ILiquidityBuffer lb) public reinitializer(2) notZeroAddress(address(lb)) {
        liquidityBuffer = lb;
    }

    /// @notice Interface for users to stake their ETH with the protocol. Note: when allowlist is enabled, only users
    /// with the allowlist can stake.
    /// @dev Mints the corresponding amount of mETH (relative to the stake's share in the total ETH controlled by the
    /// protocol) to the user.
    /// @param minMETHAmount The minimum amount of mETH that the user expects to receive in return.
    function stake(uint256 minMETHAmount) external payable {
        if (pauser.isStakingPaused()) {
            revert Paused();
        }

        if (isStakingAllowlist) {
            _checkRole(STAKING_ALLOWLIST_ROLE);
        }

        if (msg.value < minimumStakeBound) {
            revert MinimumStakeBoundNotSatisfied();
        }

        uint256 mETHMintAmount = ethToMETH(msg.value);
        if (mETHMintAmount + mETH.totalSupply() > maximumMETHSupply) {
            revert MaximumMETHSupplyExceeded();
        }
        if (mETHMintAmount < minMETHAmount) {
            revert StakeBelowMinimumMETHAmount(mETHMintAmount, minMETHAmount);
        }

        // Increment unallocated ETH after calculating the exchange rate to ensure
        // a consistent rate.
        unallocatedETH += msg.value;

        emit Staked(msg.sender, msg.value, mETHMintAmount);
        mETH.mint(msg.sender, mETHMintAmount);
    }

    /// @notice Interface for users to submit a request to unstake.
    /// @dev Transfers the specified amount of mETH to the staking contract and locks it there until it is burned on
    /// request claim. The staking contract must therefore be approved to move the user's mETH on their behalf.
    /// @param methAmount The amount of mETH to unstake.
    /// @param minETHAmount The minimum amount of ETH that the user expects to receive.
    /// @return The request ID.
    function unstakeRequest(uint128 methAmount, uint128 minETHAmount) external returns (uint256) {
        return _unstakeRequest(methAmount, minETHAmount);
    }

    /// @notice Interface for users to submit a request to unstake with an ERC20 permit.
    /// @dev Transfers the specified amount of mETH to the staking contract and locks it there until it is burned on
    /// request claim. The permit must therefore allow the staking contract to move the user's mETH on their behalf.
    /// @return The request ID.
    function unstakeRequestWithPermit(
        uint128 methAmount,
        uint128 minETHAmount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256) {
        SafeERC20Upgradeable.safePermit(mETH, msg.sender, address(this), methAmount, deadline, v, r, s);
        return _unstakeRequest(methAmount, minETHAmount);
    }

    /// @notice Processes a user's request to unstake by transferring the corresponding mETH to the staking contract
    /// and creating the request on the unstake requests manager.
    /// @param methAmount The amount of mETH to unstake.
    /// @param minETHAmount The minimum amount of ETH that the user expects to receive.
    function _unstakeRequest(uint128 methAmount, uint128 minETHAmount) internal returns (uint256) {
        if (pauser.isUnstakeRequestsAndClaimsPaused()) {
            revert Paused();
        }

        if (methAmount < minimumUnstakeBound) {
            revert MinimumUnstakeBoundNotSatisfied();
        }

        uint128 ethAmount = uint128(mETHToETH(methAmount));
        if (ethAmount < minETHAmount) {
            revert UnstakeBelowMinimumETHAmount(ethAmount, minETHAmount);
        }

        uint256 requestID =
            unstakeRequestsManager.create({requester: msg.sender, mETHLocked: methAmount, ethRequested: ethAmount});
        emit UnstakeRequested({id: requestID, staker: msg.sender, ethAmount: ethAmount, mETHLocked: methAmount});

        SafeERC20Upgradeable.safeTransferFrom(mETH, msg.sender, address(unstakeRequestsManager), methAmount);

        return requestID;
    }

    /// @notice Interface for users to claim their finalized and filled unstaking requests.
    /// @dev See also {UnstakeRequestsManager} for a more detailed explanation of finalization and request filling.
    function claimUnstakeRequest(uint256 unstakeRequestID) external {
        if (pauser.isUnstakeRequestsAndClaimsPaused()) {
            revert Paused();
        }
        emit UnstakeRequestClaimed(unstakeRequestID, msg.sender);
        unstakeRequestsManager.claim(unstakeRequestID, msg.sender);
    }

    /// @notice Returns the status of the request whether it is finalized and how much ETH has been filled.
    /// See also {UnstakeRequestsManager.requestInfo} for a more detailed explanation of finalization and request
    /// filling.
    /// @param unstakeRequestID The ID of the unstake request.
    /// @return bool indicating if the unstake request is finalized, and the amount of ETH that has been filled.
    function unstakeRequestInfo(uint256 unstakeRequestID) external view returns (bool, uint256) {
        return unstakeRequestsManager.requestInfo(unstakeRequestID);
    }

    /// @notice Withdraws any surplus from the unstake requests manager.
    /// @dev The request manager is expected to return the funds by pushing them using
    /// {receiveFromUnstakeRequestsManager}.
    function reclaimAllocatedETHSurplus() external onlyRole(STAKING_MANAGER_ROLE) {
        // Calls the receiveFromUnstakeRequestsManager() where we perform
        // the accounting.
        unstakeRequestsManager.withdrawAllocatedETHSurplus();
    }

    /// @notice Allocates ETH from the unallocatedETH balance to the unstake requests manager to fill pending requests
    /// and adds to the allocatedETHForDeposits balance that is used to initiate new validators.
    function allocateETH(uint256 allocateToUnstakeRequestsManager, uint256 allocateToDeposits, uint256 allocateToLiquidityBuffer)
        external
        onlyRole(ALLOCATOR_SERVICE_ROLE)
    {
        if (pauser.isAllocateETHPaused()) {
            revert Paused();
        }

        if (allocateToUnstakeRequestsManager + allocateToDeposits + allocateToLiquidityBuffer > unallocatedETH) {
            revert NotEnoughUnallocatedETH();
        }

        unallocatedETH -= allocateToUnstakeRequestsManager + allocateToDeposits + allocateToLiquidityBuffer;

        if (allocateToDeposits > 0) {
            allocatedETHForDeposits += allocateToDeposits;
            emit AllocatedETHToDeposits(allocateToDeposits);
        }

        if (allocateToUnstakeRequestsManager > 0) {
            emit AllocatedETHToUnstakeRequestsManager(allocateToUnstakeRequestsManager);
            unstakeRequestsManager.allocateETH{value: allocateToUnstakeRequestsManager}();
        }

        if (allocateToLiquidityBuffer > 0) {
            emit AllocatedETHToLiquidityBuffer(allocateToLiquidityBuffer);
            liquidityBuffer.depositETH{value: allocateToLiquidityBuffer}();
        }
    }

    /// @notice Initiates new validators by sending ETH to the beacon chain deposit contract.
    /// @dev Cannot initiate the same validator (public key) twice. Since BLS signatures cannot be feasibly verified on
    /// the EVM, the caller must carefully make sure that the sent payloads (public keys + signatures) are correct,
    /// otherwise the sent ETH will be lost.
    function initiateValidatorsWithDeposits(ValidatorParams[] calldata validators, bytes32 expectedDepositRoot)
        external
        onlyRole(INITIATOR_SERVICE_ROLE)
    {
        if (pauser.isInitiateValidatorsPaused()) {
            revert Paused();
        }
        if (validators.length == 0) {
            return;
        }

        // Check that the deposit root matches the given value. This ensures that the deposit contract state
        // has not changed since the transaction was submitted, which means that a rogue node operator cannot
        // front-run deposit transactions.
        bytes32 actualRoot = depositContract.get_deposit_root();
        if (expectedDepositRoot != actualRoot) {
            revert InvalidDepositRoot(actualRoot);
        }

        // First loop is to check that all validators are valid according to our constraints and we record the
        // validators and how much we have deposited.
        uint256 amountDeposited = 0;
        for (uint256 i = 0; i < validators.length; ++i) {
            ValidatorParams calldata validator = validators[i];

            if (usedValidators[validator.pubkey]) {
                revert PreviouslyUsedValidator();
            }

            if (validator.depositAmount < minimumDepositAmount) {
                revert MinimumValidatorDepositNotSatisfied();
            }

            if (validator.depositAmount > maximumDepositAmount) {
                revert MaximumValidatorDepositExceeded();
            }

            _requireProtocolWithdrawalAccount(validator.withdrawalCredentials);

            usedValidators[validator.pubkey] = true;
            amountDeposited += validator.depositAmount;

            emit ValidatorInitiated({
                id: keccak256(validator.pubkey),
                operatorID: validator.operatorID,
                pubkey: validator.pubkey,
                amountDeposited: validator.depositAmount
            });
        }

        if (amountDeposited > allocatedETHForDeposits) {
            revert NotEnoughDepositETH();
        }

        allocatedETHForDeposits -= amountDeposited;
        totalDepositedInValidators += amountDeposited;
        numInitiatedValidators += validators.length;

        // Second loop is to send the deposits to the deposit contract. Keeps external calls to the deposit contract
        // separate from state changes.
        for (uint256 i = 0; i < validators.length; ++i) {
            ValidatorParams calldata validator = validators[i];
            depositContract.deposit{value: validator.depositAmount}({
                pubkey: validator.pubkey,
                withdrawal_credentials: validator.withdrawalCredentials,
                signature: validator.signature,
                deposit_data_root: validator.depositDataRoot
            });
        }
    }

    /// @inheritdoc IStakingReturnsWrite
    /// @dev Intended to be the called in the same transaction initiated by reclaimAllocatedETHSurplus().
    /// This should only be called in emergency scenarios, e.g. if the unstake requests manager has cancelled
    /// unfinalized requests and there is a surplus balance.
    /// Adds the received funds to the unallocated balance.
    function receiveFromUnstakeRequestsManager() external payable onlyUnstakeRequestsManager {
        unallocatedETH += msg.value;
    }

    /// @notice Tops up the unallocated ETH balance to increase the amount of ETH in the protocol.
    /// @dev Bypasses the returns aggregator fee collection to inject ETH directly into the protocol.
    function topUp() external payable onlyRole(TOP_UP_ROLE) {
        unallocatedETH += msg.value;
    }

    /// @notice Converts from mETH to ETH using the current exchange rate.
    /// The exchange rate is given by the total supply of mETH and total ETH controlled by the protocol.
    function ethToMETH(uint256 ethAmount) public view returns (uint256) {
        // 1:1 exchange rate on the first stake.
        // Using `METH.totalSupply` over `totalControlled` to check if the protocol is in its bootstrap phase since
        // the latter can be manipulated, for example by transferring funds to the `ExecutionLayerReturnsReceiver`, and
        // therefore be non-zero by the time the first stake is made
        if (mETH.totalSupply() == 0) {
            return ethAmount;
        }

        // deltaMETH = (1 - exchangeAdjustmentRate) * (mETHSupply / totalControlled) * ethAmount
        // This rounds down to zero in the case of `(1 - exchangeAdjustmentRate) * ethAmount * mETHSupply <
        // totalControlled`.
        // While this scenario is theoretically possible, it can only be realised feasibly during the protocol's
        // bootstrap phase and if `totalControlled` and `mETHSupply` can be changed independently of each other. Since
        // the former is permissioned, and the latter is not permitted by the protocol, this cannot be exploited by an
        // attacker.
        return Math.mulDiv(
            ethAmount,
            mETH.totalSupply() * uint256(_BASIS_POINTS_DENOMINATOR - exchangeAdjustmentRate),
            totalControlled() * uint256(_BASIS_POINTS_DENOMINATOR)
        );
    }

    /// @notice Converts from ETH to mETH using the current exchange rate.
    /// The exchange rate is given by the total supply of mETH and total ETH controlled by the protocol.
    function mETHToETH(uint256 mETHAmount) public view returns (uint256) {
        // 1:1 exchange rate on the first stake.
        // Using `METH.totalSupply` over `totalControlled` to check if the protocol is in its bootstrap phase since
        // the latter can be manipulated, for example by transferring funds to the `ExecutionLayerReturnsReceiver`, and
        // therefore be non-zero by the time the first stake is made
        if (mETH.totalSupply() == 0) {
            return mETHAmount;
        }

        // deltaETH = (totalControlled / mETHSupply) * mETHAmount
        // This rounds down to zero in the case of `mETHAmount * totalControlled < mETHSupply`.
        // While this scenario is theoretically possible, it can only be realised feasibly during the protocol's
        // bootstrap phase and if `totalControlled` and `mETHSupply` can be changed independently of each other. Since
        // the former is permissioned, and the latter is not permitted by the protocol, this cannot be exploited by an
        // attacker.
        return Math.mulDiv(mETHAmount, totalControlled(), mETH.totalSupply());
    }

    /// @notice The total amount of ETH controlled by the protocol.
    /// @dev Sums over the balances of various contracts and the beacon chain information from the oracle.
    function totalControlled() public view returns (uint256) {
        OracleRecord memory record = oracle.latestRecord();
        uint256 total = 0;
        total += unallocatedETH;
        total += allocatedETHForDeposits;
        /// The total ETH deposited to the beacon chain must be decreased by the deposits processed by the off-chain
        /// oracle since it will be accounted for in the currentTotalValidatorBalance from that point onwards.
        total += totalDepositedInValidators - record.cumulativeProcessedDepositAmount;
        total += record.currentTotalValidatorBalance;
        total += liquidityBuffer.getAvailableBalance();
        total -= liquidityBuffer.cumulativeDrawdown();
        total += unstakeRequestsManager.balance();
        return total;
    }

    /// @notice Checks if the given withdrawal credentials are a valid 0x01 prefixed withdrawal address.
    /// @dev See also
    /// https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/validator.md#eth1_address_withdrawal_prefix
    function _requireProtocolWithdrawalAccount(bytes calldata withdrawalCredentials) internal view {
        if (withdrawalCredentials.length != 32) {
            revert InvalidWithdrawalCredentialsWrongLength(withdrawalCredentials.length);
        }

        // Check the ETH1_ADDRESS_WITHDRAWAL_PREFIX and that all other bytes are zero.
        bytes12 prefixAndPadding = bytes12(withdrawalCredentials[:12]);
        if (prefixAndPadding != 0x010000000000000000000000) {
            revert InvalidWithdrawalCredentialsNotETH1(prefixAndPadding);
        }

        address addr = address(bytes20(withdrawalCredentials[12:32]));
        if (addr != withdrawalWallet) {
            revert InvalidWithdrawalCredentialsWrongAddress(addr);
        }
    }

    /// @inheritdoc IStakingReturnsWrite
    /// @dev Adds the received funds to the unallocated balance.
    function receiveReturns() external payable onlyReturnsAggregator {
        emit ReturnsReceived(msg.value);
        unallocatedETH += msg.value;
    }

    /// @dev Adds the received funds to the unallocated balance.
    function receiveReturnsFromLiquidityBuffer() external payable onlyLiquidityBuffer {
        emit ReturnsReceivedFromLiquidityBuffer(msg.value);
        unallocatedETH += msg.value;
    }

    /// @notice Ensures that the caller is the returns aggregator.
    modifier onlyReturnsAggregator() {
        if (msg.sender != returnsAggregator) {
            revert NotReturnsAggregator();
        }
        _;
    }

    /// @notice Ensures that the caller is the returns aggregator.
    modifier onlyLiquidityBuffer() {
        if (msg.sender != address(liquidityBuffer)) {
            revert NotLiquidityBuffer();
        }
        _;
    }

    /// @notice Ensures that the caller is the unstake requests manager.
    modifier onlyUnstakeRequestsManager() {
        if (msg.sender != address(unstakeRequestsManager)) {
            revert NotUnstakeRequestsManager();
        }
        _;
    }

    /// @notice Ensures that the given address is not the zero address.
    modifier notZeroAddress(address addr) {
        if (addr == address(0)) {
            revert ZeroAddress();
        }
        _;
    }

    /// @notice Sets the minimum amount of ETH users can stake.
    function setMinimumStakeBound(uint256 minimumStakeBound_) external onlyRole(STAKING_MANAGER_ROLE) {
        minimumStakeBound = minimumStakeBound_;
        emit ProtocolConfigChanged(
            this.setMinimumStakeBound.selector, "setMinimumStakeBound(uint256)", abi.encode(minimumStakeBound_)
        );
    }

    /// @notice Sets the minimum amount of mETH users can unstake.
    function setMinimumUnstakeBound(uint256 minimumUnstakeBound_) external onlyRole(STAKING_MANAGER_ROLE) {
        minimumUnstakeBound = minimumUnstakeBound_;
        emit ProtocolConfigChanged(
            this.setMinimumUnstakeBound.selector, "setMinimumUnstakeBound(uint256)", abi.encode(minimumUnstakeBound_)
        );
    }

    /// @notice Sets the staking adjust rate.
    function setExchangeAdjustmentRate(uint16 exchangeAdjustmentRate_) external onlyRole(STAKING_MANAGER_ROLE) {
        if (exchangeAdjustmentRate_ > _MAX_EXCHANGE_ADJUSTMENT_RATE) {
            revert InvalidConfiguration();
        }

        // even though this check is redundant with the one above, this function will be rarely used so we keep it as a
        // reminder for future upgrades that this must never be violated.
        assert(exchangeAdjustmentRate_ <= _BASIS_POINTS_DENOMINATOR);

        exchangeAdjustmentRate = exchangeAdjustmentRate_;
        emit ProtocolConfigChanged(
            this.setExchangeAdjustmentRate.selector,
            "setExchangeAdjustmentRate(uint16)",
            abi.encode(exchangeAdjustmentRate_)
        );
    }

    /// @notice Sets the minimum amount of ETH that the staking contract can send to the deposit contract to initiate
    /// new validators.
    function setMinimumDepositAmount(uint256 minimumDepositAmount_) external onlyRole(STAKING_MANAGER_ROLE) {
        minimumDepositAmount = minimumDepositAmount_;
        emit ProtocolConfigChanged(
            this.setMinimumDepositAmount.selector, "setMinimumDepositAmount(uint256)", abi.encode(minimumDepositAmount_)
        );
    }

    /// @notice Sets the maximum amount of ETH that the staking contract can send to the deposit contract to initiate
    /// new validators.
    function setMaximumDepositAmount(uint256 maximumDepositAmount_) external onlyRole(STAKING_MANAGER_ROLE) {
        maximumDepositAmount = maximumDepositAmount_;
        emit ProtocolConfigChanged(
            this.setMaximumDepositAmount.selector, "setMaximumDepositAmount(uint256)", abi.encode(maximumDepositAmount_)
        );
    }

    /// @notice Sets the maximumMETHSupply variable.
    /// Note: We intentionally allow this to be set lower than the current totalSupply so that the amount can be
    /// adjusted downwards by unstaking.
    /// See also {maximumMETHSupply}.
    function setMaximumMETHSupply(uint256 maximumMETHSupply_) external onlyRole(STAKING_MANAGER_ROLE) {
        maximumMETHSupply = maximumMETHSupply_;
        emit ProtocolConfigChanged(
            this.setMaximumMETHSupply.selector, "setMaximumMETHSupply(uint256)", abi.encode(maximumMETHSupply_)
        );
    }

    /// @notice Sets the address to receive beacon chain withdrawals (i.e. validator rewards and exits).
    /// @dev Changing this variable will not have an immediate effect as all exisiting validators will still have the
    /// original value set.
    function setWithdrawalWallet(address withdrawalWallet_)
        external
        onlyRole(STAKING_MANAGER_ROLE)
        notZeroAddress(withdrawalWallet_)
    {
        withdrawalWallet = withdrawalWallet_;
        emit ProtocolConfigChanged(
            this.setWithdrawalWallet.selector, "setWithdrawalWallet(address)", abi.encode(withdrawalWallet_)
        );
    }

    /// @notice Sets the staking allowlist flag.
    function setStakingAllowlist(bool isStakingAllowlist_) external onlyRole(STAKING_MANAGER_ROLE) {
        isStakingAllowlist = isStakingAllowlist_;
        emit ProtocolConfigChanged(
            this.setStakingAllowlist.selector, "setStakingAllowlist(bool)", abi.encode(isStakingAllowlist_)
        );
    }

    receive() external payable {
        revert DoesNotReceiveETH();
    }

    fallback() external payable {
        revert DoesNotReceiveETH();
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```solidity
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 *
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts.
     *
     * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
     * constructor.
     *
     * Emits an {Initialized} event.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * A reinitializer may be used after the original initialization step. This is essential to configure modules that
     * are added through upgrades and that require initialization.
     *
     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
     * cannot be nested. If one is invoked in the context of another, execution will revert.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     *
     * WARNING: setting the version to 255 will prevent any future reinitialization.
     *
     * Emits an {Initialized} event.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     *
     * Emits an {Initialized} event the first time it is successfully executed.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized != type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**
     * @dev Returns the highest version that has been initialized. See {reinitializer}.
     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**
     * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControlEnumerable.sol)

pragma solidity ^0.8.0;

import "./IAccessControlEnumerableUpgradeable.sol";
import "./AccessControlUpgradeable.sol";
import "../utils/structs/EnumerableSetUpgradeable.sol";
import "../proxy/utils/Initializable.sol";

/**
 * @dev Extension of {AccessControl} that allows enumerating the members of each role.
 */
abstract contract AccessControlEnumerableUpgradeable is Initializable, IAccessControlEnumerableUpgradeable, AccessControlUpgradeable {
    function __AccessControlEnumerable_init() internal onlyInitializing {
    }

    function __AccessControlEnumerable_init_unchained() internal onlyInitializing {
    }
    using EnumerableSetUpgradeable for EnumerableSetUpgradeable.AddressSet;

    mapping(bytes32 => EnumerableSetUpgradeable.AddressSet) private _roleMembers;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlEnumerableUpgradeable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view virtual override returns (address) {
        return _roleMembers[role].at(index);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view virtual override returns (uint256) {
        return _roleMembers[role].length();
    }

    /**
     * @dev Overload {_grantRole} to track enumerable memberships
     */
    function _grantRole(bytes32 role, address account) internal virtual override {
        super._grantRole(role, account);
        _roleMembers[role].add(account);
    }

    /**
     * @dev Overload {_revokeRole} to track enumerable memberships
     */
    function _revokeRole(bytes32 role, address account) internal virtual override {
        super._revokeRole(role, account);
        _roleMembers[role].remove(account);
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 amount) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20Upgradeable.sol";
import "../extensions/IERC20PermitUpgradeable.sol";
import "../../../utils/AddressUpgradeable.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20Upgradeable {
    using AddressUpgradeable for address;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20Upgradeable token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20Upgradeable token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20Upgradeable token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20Upgradeable token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20Upgradeable token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
     * 0 before setting it to a non-zero value.
     */
    function forceApprove(IERC20Upgradeable token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20PermitUpgradeable token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20Upgradeable token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20Upgradeable token, bytes memory data) private returns (bool) {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && AddressUpgradeable.isContract(address(token));
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

interface ProtocolEvents {
    /// @notice Emitted when a protocol configuration has been updated.
    /// @param setterSelector The selector of the function that updated the configuration.
    /// @param setterSignature The signature of the function that updated the configuration.
    /// @param value The abi-encoded data passed to the function that updated the configuration. Since this event will
    /// only be emitted by setters, this data corresponds to the updated values in the protocol configuration.
    event ProtocolConfigChanged(bytes4 indexed setterSelector, string setterSignature, bytes value);
}

// ┏━━━┓━┏┓━┏┓━━┏━━━┓━━┏━━━┓━━━━┏━━━┓━━━━━━━━━━━━━━━━━━━┏┓━━━━━┏━━━┓━━━━━━━━━┏┓━━━━━━━━━━━━━━┏┓━
// ┃┏━━┛┏┛┗┓┃┃━━┃┏━┓┃━━┃┏━┓┃━━━━┗┓┏┓┃━━━━━━━━━━━━━━━━━━┏┛┗┓━━━━┃┏━┓┃━━━━━━━━┏┛┗┓━━━━━━━━━━━━┏┛┗┓
// ┃┗━━┓┗┓┏┛┃┗━┓┗┛┏┛┃━━┃┃━┃┃━━━━━┃┃┃┃┏━━┓┏━━┓┏━━┓┏━━┓┏┓┗┓┏┛━━━━┃┃━┗┛┏━━┓┏━┓━┗┓┏┛┏━┓┏━━┓━┏━━┓┗┓┏┛
// ┃┏━━┛━┃┃━┃┏┓┃┏━┛┏┛━━┃┃━┃┃━━━━━┃┃┃┃┃┏┓┃┃┏┓┃┃┏┓┃┃━━┫┣┫━┃��━━━━━┃┃━┏┓┃┏┓┃┃┏┓┓━┃┃━┃┏┛┗━┓┃━┃┏━┛━┃┃━
// ┃┗━━┓━┃┗┓┃┃┃┃┃┃┗━┓┏┓┃┗━┛┃━━━━┏┛┗┛┃┃┃━┫┃┗┛┃┃┗┛┃┣━━┃┃┃━┃┗┓━━━━┃┗━┛┃┃┗┛┃┃┃┃┃━┃┗┓┃┃━┃┗┛┗┓┃┗━┓━┃┗┓
// ┗━━━┛━┗━┛┗┛┗┛┗━━━┛┗┛┗━━━┛━━━━┗━━━┛┗━━┛┃┏━┛┗━━┛┗━━┛┗┛━┗━┛━━━━┗━━━┛┗━━┛┗┛┗┛━┗━┛┗┛━┗━━━┛┗━━┛━┗━┛
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┃┃━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┗┛━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
//
// From: https://github.com/ethereum/consensus-specs/blob/dev/solidity_deposit_contract/deposit_contract.sol

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.20;

// This interface is designed to be compatible with the Vyper version.
/// @notice This is the Ethereum 2.0 deposit contract interface.
/// For more information see the Phase 0 specification under https://github.com/ethereum/eth2.0-specs
interface IDepositContract {
    /// @notice A processed deposit event.
    event DepositEvent(bytes pubkey, bytes withdrawal_credentials, bytes amount, bytes signature, bytes index);

    /// @notice Submit a Phase 0 DepositData object.
    /// @param pubkey A BLS12-381 public key.
    /// @param withdrawal_credentials Commitment to a public key for withdrawals.
    /// @param signature A BLS12-381 signature.
    /// @param deposit_data_root The SHA-256 hash of the SSZ-encoded DepositData object.
    /// Used as a protection against malformed input.
    function deposit(
        bytes calldata pubkey,
        bytes calldata withdrawal_credentials,
        bytes calldata signature,
        bytes32 deposit_data_root
    ) external payable;

    /// @notice Query the current deposit root hash.
    /// @return The deposit root hash.
    function get_deposit_root() external view returns (bytes32);

    /// @notice Query the current deposit count.
    /// @return The deposit count encoded as a little endian 64-bit number.
    function get_deposit_count() external view returns (bytes memory);
}

// Based on official specification in https://eips.ethereum.org/EIPS/eip-165
interface ERC165 {
    /// @notice Query if a contract implements an interface
    /// @param interfaceId The interface identifier, as specified in ERC-165
    /// @dev Interface identification is specified in ERC-165. This function
    ///  uses less than 30,000 gas.
    /// @return `true` if the contract implements `interfaceId` and
    ///  `interfaceId` is not 0xffffffff, `false` otherwise
    function supportsInterface(bytes4 interfaceId) external pure returns (bool);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {IERC20Upgradeable} from "openzeppelin-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import {IERC20PermitUpgradeable} from "openzeppelin-upgradeable/token/ERC20/extensions/IERC20PermitUpgradeable.sol";

interface IMETH is IERC20Upgradeable, IERC20PermitUpgradeable {
    /// @notice Mint mETH to the staker.
    /// @param staker The address of the staker.
    /// @param amount The amount of tokens to mint.
    function mint(address staker, uint256 amount) external;

    /// @notice Burn mETH from the msg.sender.
    /// @param amount The amount of tokens to burn.
    function burn(uint256 amount) external;
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

/// @notice The records stored by the oracle contract informing the protocol about consensus layer activity. It is
/// computed and reported by off-chain oracle services.
/// @dev "current" quantities refer to the state at the `updateEndBlock` block number.
/// @dev "cumulative" quantities refer to sums up to the `updateEndBlock` block number.
/// @dev "window" quantities refer to sums over the block window between the `updateStartBlock` and `updateEndBlock`.
/// @param updateStartBlock The start of the oracle record block window. This should be 1 higher than the
/// updateEndBlock of the previous oracle record.
/// @param updateEndBlock The block number up to which this oracle record was computed (inclusive).
/// @param currentNumValidatorsNotWithdrawable The number of our validators that do not have the withdrawable status.
/// @param cumulativeNumValidatorsWithdrawable The total number of our validators that have the withdrawable status.
/// These validators have either the status `withdrawal_possible` or `withdrawal_done`. Note: validators can
/// fluctuate between the two statuses due to top ups.
/// @param windowWithdrawnPrincipalAmount The amount of principal that has been withdrawn from the consensus layer in
/// the analyzed block window.
/// @param windowWithdrawnRewardAmount The amount of rewards that has been withdrawn from the consensus layer in the
/// analysed block window.
/// @param currentTotalValidatorBalance The total amount of ETH in the consensus layer (i.e. the sum of all validator
/// balances). This is one of the major quantities to compute the total value controlled by the protocol.
/// @param cumulativeProcessedDepositAmount The total amount of ETH that has been deposited into and processed by the
/// consensus layer. This is used to prevent double counting of the ETH deposited to the consensus layer.
struct OracleRecord {
    uint64 updateStartBlock;
    uint64 updateEndBlock;
    uint64 currentNumValidatorsNotWithdrawable;
    uint64 cumulativeNumValidatorsWithdrawable;
    uint128 windowWithdrawnPrincipalAmount;
    uint128 windowWithdrawnRewardAmount;
    uint128 currentTotalValidatorBalance;
    uint128 cumulativeProcessedDepositAmount;
}

interface IOracleWrite {
    /// @notice Pushes a new record to the oracle.
    function receiveRecord(OracleRecord calldata record) external;
}

interface IOracleReadRecord {
    /// @notice Returns the latest validated record.
    /// @return `OracleRecord` The latest validated record.
    function latestRecord() external view returns (OracleRecord calldata);

    /// @notice Returns the record at the given index.
    /// @param idx The index of the record to retrieve.
    /// @return `OracleRecord` The record at the given index.
    function recordAt(uint256 idx) external view returns (OracleRecord calldata);

    /// @notice Returns the number of records in the oracle.
    /// @return `uint256` The number of records in the oracle.
    function numRecords() external view returns (uint256);
}

interface IOracleReadPending {
    /// @notice Returns the pending update.
    /// @return `OracleRecord` The pending update.
    function pendingUpdate() external view returns (OracleRecord calldata);

    /// @notice Indicates whether an oracle update is pending, i.e. if it was rejected by `_sanityCheckUpdate`.
    function hasPendingUpdate() external view returns (bool);
}

interface IOracleRead is IOracleReadRecord, IOracleReadPending {}

interface IOracleManager {
    /// @notice Sets the new oracle updater for the contract.
    /// @param newUpdater The new oracle updater.
    function setOracleUpdater(address newUpdater) external;
}

interface IOracle is IOracleWrite, IOracleRead, IOracleManager {}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

interface IPauserRead {
    /// @notice Flag indicating if staking is paused.
    function isStakingPaused() external view returns (bool);

    /// @notice Flag indicating if unstake requests are paused.
    function isUnstakeRequestsAndClaimsPaused() external view returns (bool);

    /// @notice Flag indicating if initiate validators is paused
    function isInitiateValidatorsPaused() external view returns (bool);

    /// @notice Flag indicating if submit oracle records is paused.
    function isSubmitOracleRecordsPaused() external view returns (bool);

    /// @notice Flag indicating if allocate ETH is paused.
    function isAllocateETHPaused() external view returns (bool);

    /// @notice Flag indicating if liquidity buffer is paused.
    function isLiquidityBufferPaused() external view returns (bool);
}

interface IPauserWrite {
    /// @notice Pauses all actions.
    function pauseAll() external;
}

interface IPauser is IPauserRead, IPauserWrite {}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

interface IStakingInitiationRead {
    /// @notice The total amount of ETH sent to the beacon chain deposit contract.
    function totalDepositedInValidators() external view returns (uint256);

    /// @notice The number of validators initiated by the staking contract.
    function numInitiatedValidators() external view returns (uint256);

    /// @notice The block number at which the staking contract has been initialised.
    function initializationBlockNumber() external view returns (uint256);
}

interface IStakingReturnsWrite {
    /// @notice Accepts funds sent by the returns aggregator.
    function receiveReturns() external payable;

    /// @notice Accepts funds sent by the unstake requests manager.
    function receiveFromUnstakeRequestsManager() external payable;

    /// @notice Accepts funds sent by the liquidity buffer.
    function receiveReturnsFromLiquidityBuffer() external payable;

    /// @notice Top up staking contract.
    function topUp() external payable;
}

interface IStaking is IStakingInitiationRead, IStakingReturnsWrite {}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {Staking} from "../Staking.sol";

/// @notice An unstake request is stored in the UnstakeRequestsManager and records the information required to
/// fulfill an unstake request claim.
/// @param id The unique ID of the unstake request.
/// @param requester The address of the user that requested the unstake.
/// @param mETHLocked The amount of mETH that was locked when the unstake request was created. The amount of mETH
/// will be burned once the request has been claimed.
/// @param ethRequested The amount of ETH that was requested when the unstake request was created.
/// @param cumulativeETHRequested The cumulative amount of ETH that had been requested in this request and all unstake
/// requests before this one.
/// @param blockNumber The block number at which the unstake request was created.
struct UnstakeRequest {
    uint64 blockNumber;
    address requester;
    uint128 id;
    uint128 mETHLocked;
    uint128 ethRequested;
    uint128 cumulativeETHRequested;
}

interface IUnstakeRequestsManagerWrite {
    /// @notice Creates a new unstake request and adds it to the unstake requests array.
    /// @param requester The address of the entity making the unstake request.
    /// @param mETHLocked The amount of mETH tokens currently locked in the contract.
    /// @param ethRequested The amount of ETH being requested for unstake.
    /// @return The ID of the new unstake request.
    function create(address requester, uint128 mETHLocked, uint128 ethRequested) external returns (uint256);

    /// @notice Allows the requester to claim their unstake request after it has been finalized.
    /// @param requestID The ID of the unstake request to claim.
    /// @param requester The address of the entity claiming the unstake request.
    function claim(uint256 requestID, address requester) external;

    /// @notice Cancels a batch of the latest unfinalized unstake requests.
    /// @param maxCancel The maximum number of requests to cancel.
    /// @return A boolean indicating if there are more unstake requests to cancel.
    function cancelUnfinalizedRequests(uint256 maxCancel) external returns (bool);

    /// @notice Allocate ether into the contract.
    function allocateETH() external payable;

    /// @notice Withdraws surplus ETH from the allocatedETHForClaims.
    function withdrawAllocatedETHSurplus() external;
}

interface IUnstakeRequestsManagerRead {
    /// @notice Retrieves a specific unstake request based on its ID.
    /// @param requestID The ID of the unstake request to fetch.
    /// @return The UnstakeRequest struct corresponding to the given ID.
    function requestByID(uint256 requestID) external view returns (UnstakeRequest memory);

    /// @notice Returns the status of the request whether it is finalized and how much ETH that has been filled.
    /// @param requestID The ID of the unstake request.
    /// @return bool indicating if the request is finalized, and the amount of ETH that has been filled.
    function requestInfo(uint256 requestID) external view returns (bool, uint256);

    /// @notice Calculates the amount of ether allocated in the contract exceeding the total required to pay unclaimed.
    /// @return The amount of surplus allocatedETH.
    function allocatedETHSurplus() external view returns (uint256);

    /// @notice Calculates the amount of ether that is needed to fulfill the unstake requests.
    /// @return The amount of allocatedETH deficit.
    function allocatedETHDeficit() external view returns (uint256);

    /// @notice Calculates the amount of ether that has been allocated but not yet claimed.
    /// @return The total amount of ether that is waiting to be claimed.
    function balance() external view returns (uint256);
}

interface IUnstakeRequestsManager is IUnstakeRequestsManagerRead, IUnstakeRequestsManagerWrite {}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

/**
 * @title ILiquidityBuffer
 * @notice Interface for LiquidityBuffer contract that manages liquidity allocation to position managers
 */
interface ILiquidityBuffer {
    struct PositionManagerConfig {
        address managerAddress;           // position manager contract address
        uint256 allocationCap;           // maximum allocation limit for this manager
        bool isActive;                   // whether the position manager is operational
    }

    struct PositionAccountant {
        uint256 allocatedBalance; // total allocated balance to this manager
        uint256 interestClaimedFromManager;  // total interest claimed from this manager
    }

    /// @notice Deposit funds from staking contract
    function depositETH() external payable;

    /// @notice Receive funds from position manager
    function receiveETHFromPositionManager() external payable;
    
    /// @notice Get available principal balance for allocation
    /// @dev Formula: totalFundsReceived - totalFundsReturned
    function getAvailableBalance() external view returns (uint256);

    function cumulativeDrawdown() external view returns (uint256);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControlEnumerable.sol)

pragma solidity ^0.8.0;

import "./IAccessControlUpgradeable.sol";

/**
 * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
 */
interface IAccessControlEnumerableUpgradeable is IAccessControlUpgradeable {
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) external view returns (address);

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) external view returns (uint256);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/AccessControl.sol)

pragma solidity ^0.8.0;

import "./IAccessControlUpgradeable.sol";
import "../utils/ContextUpgradeable.sol";
import "../utils/StringsUpgradeable.sol";
import "../utils/introspection/ERC165Upgradeable.sol";
import "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```solidity
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```solidity
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it. We recommend using {AccessControlDefaultAdminRules}
 * to enforce additional security measures for this role.
 */
abstract contract AccessControlUpgradeable is Initializable, ContextUpgradeable, IAccessControlUpgradeable, ERC165Upgradeable {
    function __AccessControl_init() internal onlyInitializing {
    }

    function __AccessControl_init_unchained() internal onlyInitializing {
    }
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role);
        _;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlUpgradeable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view virtual override returns (bool) {
        return _roles[role].members[account];
    }

    /**
     * @dev Revert with a standard message if `_msgSender()` is missing `role`.
     * Overriding this function changes the behavior of the {onlyRole} modifier.
     *
     * Format of the revert message is described in {_checkRole}.
     *
     * _Available since v4.6._
     */
    function _checkRole(bytes32 role) internal view virtual {
        _checkRole(role, _msgSender());
    }

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        StringsUpgradeable.toHexString(account),
                        " is missing role ",
                        StringsUpgradeable.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view virtual override returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     *
     * May emit a {RoleGranted} event.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     *
     * May emit a {RoleRevoked} event.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     *
     * May emit a {RoleRevoked} event.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * May emit a {RoleGranted} event.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     *
     * May emit a {RoleGranted} event.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     *
     * May emit a {RoleRevoked} event.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/structs/EnumerableSet.sol)
// This file was procedurally generated from scripts/generate/templates/EnumerableSet.js.

pragma solidity ^0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```solidity
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 *
 * [WARNING]
 * ====
 * Trying to delete such a structure from storage will likely result in data corruption, rendering the structure
 * unusable.
 * See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
 *
 * In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an
 * array of EnumerableSet.
 * ====
 */
library EnumerableSetUpgradeable {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastValue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastValue;
                // Update the index for the moved value
                set._indexes[lastValue] = valueIndex; // Replace lastValue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        bytes32[] memory store = _values(set._inner);
        bytes32[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20Upgradeable {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 amount) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20PermitUpgradeable {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20Upgradeable.sol";
import "./extensions/IERC20MetadataUpgradeable.sol";
import "../../utils/ContextUpgradeable.sol";
import "../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20Upgradeable is Initializable, ContextUpgradeable, IERC20Upgradeable, IERC20MetadataUpgradeable {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    function __ERC20_init(string memory name_, string memory symbol_) internal onlyInitializing {
        __ERC20_init_unchained(name_, symbol_);
    }

    function __ERC20_init_unchained(string memory name_, string memory symbol_) internal onlyInitializing {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(address from, address to, uint256 amount) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[45] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControlUpgradeable {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

import "./math/MathUpgradeable.sol";
import "./math/SignedMathUpgradeable.sol";

/**
 * @dev String operations.
 */
library StringsUpgradeable {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = MathUpgradeable.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toString(int256 value) internal pure returns (string memory) {
        return string(abi.encodePacked(value < 0 ? "-" : "", toString(SignedMathUpgradeable.abs(value))));
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, MathUpgradeable.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }

    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return keccak256(bytes(a)) == keccak256(bytes(b));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./IERC165Upgradeable.sol";
import "../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165Upgradeable is Initializable, IERC165Upgradeable {
    function __ERC165_init() internal onlyInitializing {
    }

    function __ERC165_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165Upgradeable).interfaceId;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20Upgradeable.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20MetadataUpgradeable is IERC20Upgradeable {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library MathUpgradeable {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard signed math utilities missing in the Solidity language.
 */
library SignedMathUpgradeable {
    /**
     * @dev Returns the largest of two signed numbers.
     */
    function max(int256 a, int256 b) internal pure returns (int256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two signed numbers.
     */
    function min(int256 a, int256 b) internal pure returns (int256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two signed numbers without overflow.
     * The result is rounded towards zero.
     */
    function average(int256 a, int256 b) internal pure returns (int256) {
        // Formula from the book "Hacker's Delight"
        int256 x = (a & b) + ((a ^ b) >> 1);
        return x + (int256(uint256(x) >> 255) & (a ^ b));
    }

    /**
     * @dev Returns the absolute unsigned value of a signed value.
     */
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165Upgradeable {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}